Island



. PTBNTED JAN. 19, 1904.

F- Ri V LATHE GHUGK. APPLIOATIOH FILD'APB. 15. 1903.

2 SHEETS-SHEET l.

I0 MODEL.

fic-5.a,

PATBNTED JAN. 19, 1994.

P.` R. INMAN.

LATHE CHUCK!f APPL1oAT1oN-r1LnD un. 1s, 1903.

2 SHEETS-SHEET 2.

lNO MODEL.

/N KEN i No.' 749,794.

Patented January i9, 1904.

PATENT QEEICE.V

FEED E.. INMAN, 0E PEovTDENeE, RHODE ISLAND.

LATHE-CHUCK.

SPECIFICATION forming part of Letters'latent No. 749,794, dated J' annary 19. 1904.

.Application filed April 15, 1903.

`with the work-holders thereon. Fig. 2 is a plan view of the chuck when said' face-plate on line .fr of Fig. 3.

is removed therefrom and illustrates the slid- Fig. 3 is the 'same as Fig. 1, except that' itV shows the piece of wood in position upon vthe.

chuck readyto be turned and accurately 'centered and held' in place for'the turning operation. Fig. f4 is a View of the same as seen Figs. 5 and Gare plan views of modified forms of vthe face-plate, showing differentarrangements and directions of the slots. Fig. 7 is a side elevation of my invention.

My invention is an improvement in work centering and holding devices for chucks of turning-lathesg and it consists of the novel construction and combination of the several elements, as hereinafter particularly described,

' and specifically set forth inthe claims.

My invention more particularly relates to lathes for wood-turning; and it consists in providing the chucks thereof with adjustable dey vices for centering and holding the work; but

it is also well adapted for high-speed polishing-lathes for finishing metal-work, as will be hereinafter more fully stated. r

'ln the drawings, 1 represents the head of a chuck of a turning-lathe. The hub 2 of-said head has a screw-threaded bore and is fastened thereby on the end of the mandrel or shaft 3. The head 1 has an annular flange 4, which itself has an annular flange or extension 5 of less Width than that of the flange 4. The head 1 has on the side opposite thehub 2 and concentric therewith the hub 6 and is also provided with three arc shaped concentric guides or ribs 7, fixed in position, said hub 6 Serial No. 152,778. (No model.)

and guides 7 being preferably integral with'.

the head 1. The inner periphery of the ange t 4 and the outer periphery of each of the arcshaped guides or ribs 7 are undercut or beveled, as seen in Fig. 4. Thus there are formed vthree arc-shaped'dovetail channels 8 between the inner periphery of the annular ange 4 and the guides 7, as shown in Figs. 2 andV 4.

' Betweenthe several guides 7 are openings r spaces 9. The ends of said guides 7 are bev.- -eled transversely, as illustrated in Fig. 2.

In each channel 8 there is a sliding block 10 of a width to-fit in loose contact with the inner periphery of the iange4 and the adjacent guide or rib 7, as seen in Fig. 2. `Each sliding block 10 has its longitudinal sidesbeveled, so that it is in the shape of. a truncated wedge. Each block 10 is of a length exceeding that of the intermediate space 9, which is between the ends of the guides 7. In the eenter` of each sliding block 10 a screw-threaded hole 11 is made.

A circular face-plate or disk 12 has a 'eeritral circular hole 13, by which it is rotatably .mounted on the hub 6. The hub 6 is concentrically reduced in diameter, so that the faceplate 12 rests upon the shoulder so formed and is in contactwith the face of each guide 7, as

shown in Fig. 4. Said plate 12 has an annular extension or ange 14, which'fits over the edge of the ange or extension 5 of the headY 1, as seen in Fig. 4. .It has at proper intervals Spanner-holes 15 and also reamed holes, in which are seated screws 16,whieh, passing through the face-place 12, entervand engage the screw-threaded holes 11 of the sliding blocks 10.

Lever-arms 17 are pvotally mounted at one end thereof, respectively, on screws 18, which enter screw-holes tapped in the head 1 of the chuck. Each lever-arm 17 has at Vits opposite end arounded head 19, with a round hole 20 through it transversely. ed ends of the lever-arms 17 oscillate into and out of the spaces 9 between the ends of the guides' 7, as illustrated in Fig. 2.

The face-plate 12 has three slots 21, prefer ably spiral, as shown in Fig. 1, the outer ends of which are near to the circumference of the face-plate, the inner ends of which converge The free or headheads of the screws 23 are flush with the outer surface of said holders. The holders 22 freely turn on the Unthreaded portion or shank of the screws 23. r1`he holders 22 have their work-holding edges all on the same curvature,

` and their ends are cut o on the radial lines of such curvature, so that when the holders 22 are at their innermost positions they together have their work-holding edges in a true and complete circle.

The Shanks of the screws 23 are of such a diameter as to fit loosely in the slots 21 of the face-plate 12.

The wooden block orl work, which isl centered and held upon' the chuck to be operated upon, vis designated as 24 and is shown in po sition in Figs. 3 and 4.

Having thus described the parts of said device, jI will now eXplain the manner of its operation. l p

The'screws 16 are sufiiciently loosened to allow .the vface-plate 12 to be turned. The holders 22 are at or near the position indicated in Fig. 1 at the outer ends of the slots 21, respectively. A Spanner or other suitable tool is used to rotate the face-plate 12 and ,may be inserted in the holes 15 for that purpose. ,The wooden block 24 is placed and held temporarily by hand at or near the center of the face-plate 12 incontaet therewith, and the Spanner or tool -is then used to partially rotate in the direction indicated by the arrow c the face-plate 12 on the hub 6 of the head 1. The edges of the slots act as camsurfaces, and as the face-plate 12 is partially rotated in the direction of the arrow @they cause the screws 23 to follow inwardly the courses of the slots 21, and thereby the leverarms 17 are oscillated on their pivots 18, as indicated by thedotted lines in Fig. 2, and the heads 19 of said levers move in the arcs designated by dotted lines 25 in said figure. The three holders 22, swiveling freely on the screws 23, thus move inwardly at the same rate of speed toward the center, and when they come in contactwith the periphery of the bloek- 24 they automatically tit their concave edges upon said block, and thus accurately center said block, as illustrated in Figs.

3 and 4. 'lh'e screws 16 are then 'tightened up and vserve as `clamps to hold the face-plate v12 firmly to the head 1 and to `maintain the grip of the holders 22 on the block 24, the beveled surfaces of the sliding blocks 10 being drawn up into forcible contact with the beveled sides of the channel 8. While the faceplate 12 is thus partially rotating the blocks 10,

to whichthe plate or disk 12 is connected by the screws 16, slide in but cannot leave the arcshaped channels 8, Fig. 2, the screws16 havingbeen slightly loosened, as already stated; but .when the block 24 has been centered and the screws 16 have been tightened by hand all the parts are held securely and rigidly in place.

In Figs. 5 and 6 are shown modifications of the face-plate 12,- consisting of the employment of arc-shaped slots or straight slots instead of spirally-directed slots 21, as in Fig. 1. The mechanical principle involved is the same; but the gripping power of the holders 22 is greater in the case of the spiral slots 21 than in case of the otherwise-directed slots. The straight slots being shorter in extent than the others allow quicker action, though they have less holding power, whereas curved slots, whether arc shaped or spiral, though slightly less quick in action, have greater binding power. Instead of mounting the faceplate 12 on the hub 6 of the head 1 by means of the circular central aperture'13, as shown, it is obvious that a screw, pivot, or other equivalent device may be used for the same purpose. It is seen in Fig. 4 that the faceplate is so flanged that it is capable of a rotary movement within the annular iiange`5l of the` head. Therefore the hub 6 may be dispensed with, if desired, br if the hub 6 is. used for the mounting of the face-plate 12 the flange 14 of the face-plate 12 may be dispensed with. I prefer, however, to use both the hub 6 and the Harige 14, as illustrated in Fig. 4.

It is 'preferred to use a plate or disk having three slots, and consequently to have three le- IOO ver-arms and three holders; but any other suit# Y able number of these-may be used as may be found advantageous.

So far as I am aware a wood lathe-chuck has never heretofore been provided with any adjustable device either for centering the material thereon which is to be turned or for holding the same in position during operation. A common device used for these purposes has been a face-plate having a central socket into which the end of the wooden block or piece having first been cut down to a proper siz'e has been inserted and held tight by driving. A

morecommon method is to'provide a wooden i disk on the outside ot' the face-plate and 'to fasten said disk in position by s'crews which extend through the face-plate into said disk, in the rear thereof, `which wooden disk is made with a work-holding socket turned therein. It is evident that such methods are crude and inaccurate. By my device the work is automati cal ly centered with the utmost accuracy.

Moreover, the same is so iirr'nly heldin position as to be acted on perfectly by the cutting-tool however rapid may be the speed of the rotation. For lack of suitable work-holding vmeans it has'` been practically impossible to use chucks at high speeds in operating wpod-turning lathes. My invention enables the operation of such lath/es at high rates of J v l speed, Whlch have hitherto been unattainable on' Work of large diameters. i

Forypolishing metallic work my improved lathe-chuck is well adapted. While it is 'not desirable that chucks for metal-turning should be operated at high speed, because the hardness of the material necessitates a slow movement of rotation, yet for. polishing tu-rned metallic work as the resistance is very slight great speed is very desirable and conducive to fineness of finish. This has not been heretofore'possible in the use of metal-holding chucks, for they are necessarily niassiveand heavy` to adapt them to their work, and hence they cannotendure the centrifugal strain of very rapid revolutions, and besides as the work-centering and work-holding devices'on metal-holding chucks are not geoiiietrically disposed such chucks are netbalanced and if driven at high speeld are subject to great vibration, the effects oil which are in- .lurious to the work. l l

`My improved chuck has but few parts, is

very simple in construction, and is comparatively thin. All the parts are geomctrically disposed so that the chuck is perfectl,\Y balanced and runs true Without' any vibration. It dispenses with all the gearing' and other parts, which in metal-working lathes'ai'e re quired for centering and holding the work, and is consequently light and capable of very rapid action.l

I claim as a novel and useful invention and desire to secure by Letters Patent- 1. The iinprovet. work-centering mechanism for turning-lathes herein described, consisting of the combination of a head provided with a central hub, a plurality of lever-arms pivotally mounted at their'inner ends to said head, a'face-plate mounted centrally and rotatably upon said hub and having as many -openings therein for receiving the movable ends of `the lever-arms hereinafter named and also `ih'ovided with a central hub, threefslid-j ing blocks movable in the three segmental channels so formed, three lever-arms pivot-ally mounted on said surface of the head at their inner ends and solo ated that theirouter ends are movable into and out of said openingsof the annular rib, respectively. a face-plate' mounted eentrall)Y and rotatabliY uponsaid hub and having three slots converging inwardly to equispaced points, respcctively,

which are eq ually d istant from the geometrical center ot' said face-plate, three ivdrk-liltling jaws exterior to said faceplate connecte@ i and carried b y said lever-ar1ns, resi'ecti' by means ot' screws which respectively p through said work-holding jaw and through said respective slots into the lever-arms adja-V cent to said holders and three clamping-screws passing tlrough said face-plate 1nto said sliding blocks, respectively, substantially as shown and for the purpose specified.

In testimony whereof l aix my signature in presence ot' two witnesses.

FRED R. NMAN 'itnesses:

Wammes R. Pianeti, MABEL .Fos'rnit 

